节肢动物线粒体基因组碱基组成特征分析

利用93个节肢动物线粒体基因组数据,分析了线粒体基因组的碱基组成,及对氨基酸组成的影响。研究表明:(1)节肢动物线粒体基因组GC含量较低,分布范围较窄(13.28%～39.64%)。基因组GC含量与密码子第三位置的GC含量间的相关性(r=0.9432,p<0.01)比密码子第一、二位置上的相关性强。(2)在密码子的三个不同位置上均可以观察到C<->T和A<->G相互取代的现象。(3)从NC.004529和NC.003979两个序列的对比研究中可以发现碱基组成变化会引起氨基酸组成的变化,这种变化不仅体现在不同的物种之间,而且也体现在同一基因组内部的不同基因之间,这些影响可能是相互的。表明节肢动物线粒体基因组中的碱基变化是受多种因素共同作用的结果。

Analysis of base compositional properties of Arthropod mitochondrial genomes

The unusual characteristics of mitochondrion have prompted us to conduct study of mitochondrial genomes.A comprehensive analysis of base composition properties and the relationship between base composition and amino acid composition in 93 arthropod mitochondrial genomes was carried.Among arthropod mitochondrial genomes,the GC contents of the whole genomes range from 13.28% to 39.64% and are strongly correlated with that of the third codon position (r=0.9432,p<0.01).In addition,most major changes in base composition between lineages can be attributed to shifts between the proportions of C and T,A and G.Furthermore,base compositional bias could lead to amino acid bias by compared analysis of NC004529 and NC 003979.The striking variations in base composition exist both within genomes and across species. Thnese results suggest that some genome-wide factors such as GC mutational bias are important for the biased base composition in arthropod mitochondrial genomes.